Fixes#9182. Adds a link to the keyboard shortcuts popup at the
bottom-right corner of the right sidebar. A tooltip saying
`Keyboard Shortcuts(?)` has been added to the icon. The icon is
positioned using `position: fixed`.
This commit transitions all styles in app.css in the Django pipeline
to being compiled by webpack in an app-styles bundle, and renames the
various files to now be processed as SCSS.
To implement this transition, we move the old CSS file refernces in
settings.py and replace them with a bundle declared in
`webpack.assets.json` and includedn in the index.html template
Tweaked by tabbott to keep the list of files in `app.css` in
`webpack.assets.json`, and to preserve the ordering from the old
`settings.py`.
Shubham Padia
Armaan Ahluwalia